I wrote about this car's successor, the HR-X2, in September, saying:
HR-X2 was a development of the HR-X, Mazda's first hydrogen-powered vehicle. A small two-seat commuter car, the HR-X proved that a rotary engine would work on hydrogen. Mazda had bigger plans than making a few proof-of-concept concepts, though.
So there you go. You're looking at a car that features at its core (yes, in the middle) a hydrogen-powered rotary engine. If I had to guess, I'd saw this working prototype was based off of the then-upcoming Mazda AZ-1 or Suzuki Cara, albeit with a taller greenhouse and more futuristic styling.
Thanks to a digitized New York Times article from 1992, there's actually quite a bit of information online about this car. For starters, it's apparently capable of a top speed of 220 km/h (135 mph)—damn impressive for a first attempt.
Second, it was equipped with an extremely trick fuel tank, as the Times' Calvin Sims will explain:
"The Mazda tank, which is six inches thick and located in the floor of the vehicle, contains a metallic compound that absorbs the compressed hydrogen during fueling and then releases hydrogen molecules when heated to power the vehicle."
Space-efficient, I like it. It held enough fuel for a 200 km (125 mile) jaunt, which would have made it an ideal urban runabout…maybe something worth revisiting once we're able to make hydrogen more locally.
Of course, this prototype remains in Mazda's care, and apart from the sorta-production Mazda RX-8 Hydrogen RE, hydrogen rotary technology has remained out of the hands of the general public. I guess we can only hope real alternatives to gasoline appear so that companies are able to revisit this sort of vehicle…
In an ideal world, would the HR-X be the chicken or the egg?